.indexMain_box{
    width: 100%;
    height: 100%;
    /* background-color: salmon; */
    overflow-y: auto;
}
.indexMain_bigE{
    width: 100%;
    height: 400px;
    background: white;
    margin-top: 30px;
}
.indexMain_threeE{
    width: 100%;
    height: 360px;
    background: skyblue;
    display: flex;
    justify-content: space-between;
    margin-top: 40px;
}
.indexMain_threeE li {
    width: 30%;
    height: 100%;
    float: left;
    background:#FFF;
}